The objective of the proposed research is to establish an animal model system to study the virological parameters of the interaction of insecticide carrier with a viral infected host. The viruses that will be studied in the mouse include influenza type A and type B virus and encephalomyocarditis (EMC) virus. Mice will be pretreated with the insecticide carrier and then infected with virus using the intranasal and subcutaneous routes of inoculation for the influenza viruses and EMC virus respectively. They will then be observed for a prescribed period of time using a significant difference in the mean day of death and/or in the final percent survival as an index of an effect of the insecticide carrier on the viral-infected host. Additional studies will be aimed at elucidating the mechanism(s) of the effect(s) that are observed. These studies will include an assessment of the degree of viral dissemination in the tissues of the host using conventional viral infectivity assays for infectious virus and the indirect method of immunofluorescence for viral antigens, as well as conventional histopathological procedures to determine the pathological character of the effect. Experiments will also be carried out to ascertain the immunological response of the host to the virus infections relative to insecticide carrier exposure. Additional studies, if warranted on the basis of the biological effect(s) observed and/or the immunological findings, will include specific assays to assess the functionality of the component cells of the immune system to determine whether the observed effect(s) are immunologically based.